Gas operated automatic firearm



` .FHI/Enf: DI Marfil/2 52" J 47./52/0 wn M A BROWNING GAS OPERATED AUTOMATIC FIREARM Original Filed Feb. 419, 1934 l0 m-wwmm. w

WN. Q mw N www May 3, 1938.

' Patented May 3, 1938 y 13 Claims. t y The invention relatesparticularly to a gas -movable-rearward to disengage the barrel and to thus permit the barrel to be disconnected from thecasing of the gun. In accordancev with the invention a buffer is provided which is .engageable by the operating slide for-cushioning the i movement of the latter to normal position. Also 10 in accordance` with the invention, the piston tube ,f is arranged to vibrate longitudinallyso as to as'- sist in'preventing deposits in the cylinder. i f This present application constitutes a division ,15 arm, seriai'No. 711,846, nledr'ebruary 19, 1934, Awhich said co-pending application was issued as Patent No. 2,093,705 on September 21, 1937.

the embodiment of the invention which I now 20 deempreferable, but it will be understood that "only and'is 'not' to be relied upon as limiting or defining the scope of the invention, the claims 25 upon for that purpose.

- Of the drawing:

the invention. v Fig. 2 is -an enlarged fragmentary view of the `30- front portion of the firearm, this view being partly a side view and partly a longitudinal sectional .'view. 1 Fig. 3 isra view similar to Fig. 2, but showing y the parts in different relative positions. 35 Fig. 4A is a fragmentary perspective view of the rrear portion of the barrel. Fig. is a transverse sectional view taken along the line 5-5 of Fig.\2.

y 40 sectionalview showing the buffer.

Fig. 7 is aplan view showing the connection between the piston rod and operating slide.

.Referring to the drawing, I represents as an entirety the main lbreech casing, which is gen- 4.5` erally rectangular in transverse section. 'Ihe portion Ia of the casing near the front is formed f f within the casing l are feeding and firing mech- 50 particularly relate. The details of these mechanisms are disclosedin my aforesaid application SerialNq; 711,846. The casing I is closed at the rear bya plate 1, which carries the trigger 8 and control handles 9', 9. The plate 1 with the parts thereon is readily removable. 1

The barrel 2 is preferably detachably connected with the casing and has a rear cylindricaljportion 2 Awhich fits a cylindrical hole in the portion I of the casing. The rear end of the 60. barrel is provided at IU with interrupted exterv.operated firearm having the piston tube nor#V mally' connected with lthe barrel and readily` I of my co-pending application for Automatic fire- In the accompanying drawing I have shown the drawing is intended for illustrative purposes i forming a partl of. this specification being relied e Fig. l isi-a side viewjof a firearm embodying Fig. 6 is an enlargedvfragmentary longitudinal to receive the rearend of a barrel 2. Contained n anisms to, which fthe present invention does not G'AS OPERATED AUTOMATIC FIREABM e Marriner A. Browning, Ogden, Utah, assignor to y J. M. a M. S. Browning Company. Ogden, Utah, a corporation of Utah Original application; February 19, 1934, Serial No. Divided and this application March 19, 1935, Serial N0. 11,793

(ci. aia-2).

nal threads adapted to engage similar internal threads formed in the casing. When the barrel lis in the position shown in Figs. 2 and 3 it is vfirmly held in place bythe threads. It can be released by being turned through a quarter turn inthe clockwise direction. The barrel is normally held in.its locked position by means of a pinv II held by a spring I2. The rear end of the spring is T-shaped and ts a T-shaped groove yI3 in the top of the casing, and a screw I4 normally serves to prevent the spring from moving rearward out of the T-shaped slot. The pin I I can be withdrawn from the hole in the barrel by means of a suitable tool such as the head of a cartridge and then the barrel can-be turnedin the clockwise direction to disengage the interrupted threads at I0. This permits the barrel to be drawn out in rthe `forward direction. In order to avoid the necessity for using a tool to replace the barrel, the barrel is provided, as shown in Fig. 4, with a longitudinal groove I5 positioned to receive and provide clearance for the pin II. The groove I5 has a beveled surface I5 adjacent its forward end, which surface serves to cam the pin II outward when the barrel is moved inthe counter-clockwise direction into locking position. As soon as locking position is reached the rpin II -snaps intol the hole in the barrel, thus firmly locking it.

The barrel 2 is preferably provided with a se-vv ries of annular ribs 2b, 2b tol facilitate cooling. As already explained, the barrel is readily removable, and if excessive heating eventually occurs the gun may be kept in service bygremoving one barrel and substituting another.

The casing I is provided with an integral extension Id which extends forward underneath the barrel. 'I'his extension is hollow and serves to engage and retainl a lpiston tube or cylinder I 6. The tube I 6 is preferably slidable longitudinally with respect to the casing, and movement in the forward direction is limited by a shoulder I1 on the tube which engages a shoulder I8 on the casing. At its forward end the tube is connected with and supported bythe barrel.` Preferably the tube is provided at the top thereof with a T- shaped projection I9 which fits a similarly shaped T-slot formed in a'band 20 secured to the barrel. With the parts engaged, asshown in Figs; 2 and 5, the tube is held in rigid relationship to the barrel, but by moving the tube rearward it is manner already explained.l

The tube I6 is normally held invits forward engaged position by means of two links 2l and 22 which are pivotally connected with each other by a pin 23. Preferably the link 2| is u -shaped in cross section so as to partly surround and enclose the link 22. The link 2| is pivoted to the front end of the portion I'I oi' thel casing by means of a removable pin 2|, and the link 22 is pivoted tothe tube I9 by means of a pin 26. A spring pressed latch 28 is provided for holding the link 2| in its upper or normal position. It will be observed that with the parts in the positions shown in Fig. 2 the tube I 9 is held in its forward position, the link 2| substantially enclosing the link 22. When itis desired to move the tube IB in the rearward direction rthe link 2| is disengaged from the latch 29 and the link is moved downward to the position shown in Fig. 3. thus drawing the tube rearward and disengaging the projection 9 from the T-slot in the band 20. d

Longitudinally movable along the bottom v of the main casing is an operating slide 21, this slide being connected with a piston rod 29 and a piston 29 positioned within the piston tube I9. The forward end of the v.slide is bifurcated and is considerably wider than the piston rod which is secured to the bifurcated end of the slide by the pin. 21. The difference in width of` these two elements results in the shoulders 21" on the slide projecting fromvoppositeV sides of the piston rod as shown in Fig. '7.v Preferably the piston 29 is formed integrally with the rod and consists o1 one or more annular flanges thereon. IA cylinder member 30 is provided in the forward end of the tube I6, being held in place by threads, and the piston 29 accurately fits the said member.- A series of registering gas holes connect the bore of the barrel 2 with the interior of the member 30 in order that a portion ofthe gases of explosion may enter the member and acty upon the piston 29 to force it rearward from normal position.

For returning the slide 21 in the forward direction to normal position after it has been moved rearward by the pistonand piston rod there is provided va suitable action spring 3| which is preferably located near the rear of the casing I. It will be understood that the slide 21, during its rearward movement caused by the pressure of the gases and during its return movement caused by the spring, serves to operate the feeding and firing mechanisms of' the gun. The reciprocating breech bolt is shown at 49, this being connected with the slide 21 by means of links 50 and 5I.

When the slide moves forward'under the iniluence of the spring its movement is limited by a suitable buffer which surrounds the piston rod 29, an enlarged sectional view of this buffer being shown in Fig. 6. The rear portion of the piston tube |6 is formed with a cylindrical recess in which is positioned a split bushing 31 which very loosely fits the opening. The inner surface of' the split bushing 31 istapered and it engages the outer surface of a similarly'tapered bushing 39. A removable screw 39 serves tohold the two bushings in place. It will be observed that ywhen the slide 21 moves forward the shoulders 21h thereon engage the innerbushing 38 lwhich is forced into the outer bushing 31. This outer bushing by reason of the fact that it is split and is resilient offers friction which resists and stops the forward movement of the slide. When the slide again moves rearward the inner bushing 38 follows it until limited by the screw 39, the bushing thus being ready to be engaged by the slide upon its next forward movement.

In order to provide a further means for absorbing the energy of the slide at the end of its forward movement, provision may be made for operating slide and permitting the entire tube Il to move from its normal position shown in Figs. `2 ande longitudinally through a slight distance. As shown, there is provided 'a spring pressed plunger carriedby the front end portion oi' thelink 2| is provided with elongated holes for receiving the .pivot pin 2l. description it .-will be observed that the` energy of the slide is absorbed in part by the two bushings and 33 and in Preferably theslide 21 and the piston, are removable from the firearm at the rear thereof. .To enect such removal it is necessary tov remove the plate 1 with the parts carried thereby.

What I claim is: Y f

1. In an automatic nrearm, the combination of a breech casing, breech mechanism in vsaid casing, a barrel, a piston tube connected with the barrel, a gas .operated piston and an operating slideconnected with the piston rod and movable fromvand to normal position upon ringof the gun-to actuate the breech mechanlsm, a resilient buii'er surroundingl the piston rod,and means on the slide engageabie with said slide vto normal position.

2. In an automatic firearm, the combination of a breech casing, breech mechanism in said casing, a barrel, a piston tube connected with the barrel, a gas operated piston and piston rod in the tube, an operating slide connected with the piston rod and movable from and to normal position upon iring of the gun to actuate the breech mechanism, a buifer comprising two concentric frictionally engaging rings surrounding the piston rod, and means on the slide engageable with said buifer for cushioning the return movement of the slide to normal position.

3. In an automatic rearm, the combination of a breech casing, breech mechanism in said casing, a barrel, a piston tube adjacent the barrel, means connecting the tube with the barrel, a gas operated piston and piston rod in the tube movable rearward upon firing, an operating slide connected with the piston rod and movable thereby from and to normal position to actuatethe breech mechanism, and' a buifer carried' by the piston tube for cushioning the return movement of the slide to normal position. .v

4. In an automatic firearm. the combination of abreech casing, a barreLa longitudinally movrearward upon rin'g, a longitudinally movablel operating slide rigidly connected with thepiston rod to be movable-therewith, means connecting the slide vwith `the move the latter. spring means for returning the bolt in the forward direction, and a 'buffer carried by the movable piston tube at the rear end thereof and adapted when the tube is in normal position 'to beengaged by the operating slide` at the end of its forward movement. f

5.. In an automatic firearm, the combination of a breech casing, breech mechanism in said casing, a barrel. a piston tube adjacent the barrel having its forward end connected to the barrel From the foregoing part by the plunger ll. and some oi' the parts, associated therewith, including the piston rod piston rod in the tube.`

.buffer for cushioning the return movementl of the 1101iv to @name the former u and a recess in its rearward end, a gas operated piston and piston rod in the tube movable rearward upon' firing, an operating slide connected with' the piston rod and movable thereby from and to normal position to actuate the breech l mechanism, and a. buffer, surrounding the piston rod and positioned in the recess in the piston tube for cushioning the return movement of the slide to normal position.

6. In a gas operated firearm, the combination of a breech casing, breech mechanism in said casing, a barrel, gas operated means movable Lfrom and to normal position to operate the breech mechanism, a cylinder movably connected with the barrel for movement from and to normal position and having a. gas passage therein for conducting gases of explosion to said gas operated means, and means urging said cylinder to its normal position but yieldable to permit movement of the cylinder when engaged by said gas operated means upon movement of the latter to normal position.

'7. In a gas operated firearm, the combination of a breech casing, breech mechanism in said casing, a barrel, gas operated means movable from and to normal position to operate the breech' mechanism, a cylinder movably connected with the barrel and casing for movement from and to normal position and having a gas passage therein for conducting gases of explosion to said gas operated means, and means positioned between the casing and cylinder urging said cylinder to its normal position but yieldable to permit movement of the cylinder when engaged by said gas operated means upon movement of the latter to normal position.

8. Thecombination in an automatic firearm,

of a breech casing, a barrel, a longitudinally movable breech bolt in the casing, a piston tube connected with. the barrel and capable of limited longitudinal movement, a gas operated piston and piston rod in the tube movable rearward upon firing, a longitudinally movable operating slide rigidly connected with the piston rod to be movable therewith, the said slide abutting against the piston tube at the end of its forward movement,'means connecting the slide with the bolt .to enable the former to move the latter, spring means for returning the operating slide and bolt in the forward direction, and a spring means normally holding the piston tube in its rear position and permitting the tube to yield slightly when engaged by the operating slide.

9. In a gas operated automatic rearm, the combination of a breech casing, breech mechanism in said casing, a barrel, a piston tube connected with the barrel and casing for sliding movement from and to normal position and having a forward facing shoulder near the rear end, gas operated means partially positioned in the tub'e and movable from and to normal position to operate the breech mechanism and having a shoulder thereon for engagement with the piston tube, and resilient means mounted on the breech casing and engageable by the shoulder on said tube. to normally urge the tube rearward but permitting the same to yield slightly in a forward direction when engaged by the shoulder on the gas operated means.

10. In a gas operated automatic firearm, the combination of a breech casing, breech mechanism in said casing, a barrel, a cylinder connected with the barrel for movement from and to normal position, gas operated means partially positioned within the cylinder and movable from and to normal position to operate the breech mechanism, a buffer for cushioning the movement o'f the gas operated means to normal position and for transmitting motion from the said gas operated means to the cylinder, and means urging the cylinder to its normal position but yieldable to permit movement of the cylinder by the gas operated means whereby the movement of the gas operated means is further cushioned and the cylinder is caused to vibrate.

11. In a gas operated automatic firearm, the combination of a casing, breech mechanism in Said casing, a barrel, a piston tube having in the rear end thereof a recess and being slidably connected with the barrel for movement from and to normal position, a piston and piston rod reciprocatable in the tube, an operating slide connected with the piston rod for reciprocatlon therewith from and to normal position to actuate the breech mechanism, a buffer positioned in the recess in the tube for engagement by the slide to cushion its movement to normal position and for transmitting motion from the slide to the tube, and means urging the cylinder to its normal position but yieldable to permit movement of the tube by the slide whereby the movement of the slide is further cushioned and the tube is caused to vibrate.

l2. In a gas operated automatic firearm, the combination of a casing, breech mechanism in said casing, a barrel, a piston tube having a shoulder thereon and being slidably connected with the barrel for movement from and to normal position, a piston and piston rod reciprocatable in the tube, an operating slide connected with the piston rod for reciprocatlon therewith from and to normal position to actuate the breech vmechanism, a buffer for cushioning the movement of the slide to normal position and i'or transmitting motion from the slide to the tube.

and means positioned between the shoulder on the tube and the casing urging the tube to its normal position but yieldable to permit movement of the tube by the slide whereby the movement of the slide is further cushioned and the tube is caused to vibrate.

13. In a gas operatedv automatic firearm, the combination of a casing, breech mechanism in said casing, a barrel, a piston tube having at the rear end thereof a recess and a shoulder and being slidably connected with the casing and barrel for movement from and to normal position, a piston and piston rod reciprocatable in the tube, an' operating slide connected with' the piston rod for reciprocatlon therewith from and to its normal position to actuate the breech mechanism, a buffer positioned in the recess in said i tube for engagement by the slide to cushion its MARRINER A. BROWNIN'G. 

